Last time I checked this thread was about aftermarket ECU's, new options, tuning etc, lets keep this very informative thread on track as the information that has been provided is both thought provoking and interesting...

So you can achieve 18% more torque per liter (400lbs.ft if I recall correctly) than the factory's brand new all out 2011 997RSR 4.0 Ltrs race car that uses the ultimate in 4V watercooled engine technology, intake, exhaust , extraordinary heads, the latest in componentry and ECU management and a team of hundreds of the best Motorsports engineers in the world and hundreds of millions of dollars of equipment and even more R&D.

It took Porsche 10 years to improve torque per litre by 12% over 3 generations of street cars, having to move to high compression and watercooled engines.

Colin, you are a great resource and share your passion and technology as no other sponsor here, I genuinely say that it is very commendable to see how you patiently and diligently helped Macca with his issues above but slipping numbers and dynos like these over and over again in your threads can be interpreted, at best, amateurish. So many years on.

Well, I appreciate your opinion Jean, even though I cannot agree with your "party" line of what is possible.

As for amateurish, as someone who has spent todays equivalent value of a 993GT2 in my own money on a dyno installation and the subsequent development of new parts for an obsolete engine, I'll take that as a complement in relation to the tens of millions spent by Porsche achieving what they did. Given the resources we have available I also cannot see how we could ever be more professional in our approach.

In respect of reporting the results that we have achieved on the 9m dyno, I'm happy that these were an honest & accurate representation of the performance that our dyno reported (without the inclusion of "fudge factors"). Furthermore I have stated on practically every occasion that the graphs & results posted quantify the relative gains that the engines have achieved under the test conditions that we use.

Ironically I had a well respected author and engine tuner on the phone to me today offering to sell us his new ecu - apparently when he tested it on a 964 he gained 25hp over stock. Wonder where he got that idea from???

So you can achieve 18% more torque per liter (400lbs.ft if I recall correctly) than the factory's brand new all out 2011 997RSR 4.0 Ltrs race car that uses the ultimate in 4V watercooled engine technology, intake, exhaust , extraordinary heads, the latest in componentry and ECU management and a team of hundreds of the best Motorsports engineers in the world and hundreds of millions of dollars of equipment and even more R&D.

It took Porsche 10 years to improve torque per litre by 12% over 3 generations of street cars, having to move to high compression and watercooled engines.

Colin, you are a great resource and share your passion and technology as no other sponsor here, I genuinely say that it is very commendable to see how you patiently and diligently helped Macca with his issues above but slipping numbers and dynos like these over and over again in your threads can be interpreted, at best, amateurish. So many years on.

OK so we're looking at excactly matching HP/liter ratings whilst torque (and therfore BMEP) has gone up 17% of which 7% is already made up by running a 12.5:1 compression ratio (largely made possible through modern electronics).

For the sake of argument let's say the additional 10% has come from 15 additional years development by Porsche AG that flows into the 964 base engine, followed by 15 years 3rd party tuning R&D and experience.

An impressive improvement yes.....but undoable???

Let's keep in mind the fact that the 9M engines are still allowed to run racing type open intakes and non cat exhausts without having to comply with serious noise OR pollution restrictions nor having to run 100K without a rebuild.

The above is a major advantage over more modern machinery like the gt3:

Seems that I have been insensitive to some of Colin's followers, it is not my intention, this is a technical discussion forum and technical debates should therefore be welcome, and each is entitled to his opinion I hope, including disputing a tuner/sponsor's posted data.

I had compiled long ago a list of factory cars including race cars that have been built over the years by Weissach. If anyone thinks that the factory leaves anything behind in terms of maximum possible efficiency, there is no point in reading further. BMEP (similar to torque per litre) is the best measure for such efficiency by an engine as it takes into consideration engine design, management, displacement, compression, intake, exhaust, etc..

Gains between newer models are very limited in BMEP, despite all the efforts and money put behind R&D by the factory. These gains are in the single digits at best between engines of the same family, anyone posting numbers above those of the factory better have a solid story!!! The following are the gains in BMEP between the key models that Porsche has built, I tried to use same family engines for comparison, and the modifications done vs previous model it is compared to.... if there is any mistake I will be happy to correct it:

"Seems that I have been insensitive to some of Colin's followers, it is not my intention, this is a technical discussion forum and technical debates should therefore be welcome, and each is entitled to his opinion I hope, including disputing a tuner/sponsor's posted data."

Hi Jean,

Thanks for your informative post. This imo is the stuff that properly feeds a technical discussion.....one that is very welcome indeed, at least with me.

On the other end, calling someone an amateur, especially one who gives so much wealth to the forum by sharing his developments time and time again with dyno print outs etc., imo still is uncalled for.

Questioning his (or anyone elses for that matter) theories / acheviements / claims in a polite substantiated manner is a completely different animal and has fuelled some of the greatest insights and innovations in this world.

To get back at your BMEP overview (again thanks for posting). What puzzles me is the fact that the '73 RSR example mentioned in my earlier post has been left out of your argument with a BMEP of 189.

Think of it...this was back in '73 on mechanical injection and distributors. The 9M engine at 340 lb.ft as quoted by Colin has 17% more torque/liter. As already stated more than a third (7%) of this can be accounted for by the higher CR, leaving 10% to be won.

Now let's take a look at your reasoning based on the 964/993 family of engines. IMO these weren't very good engines to begin with!!! 250-285 Bhp from a 3.6 liter street engine while the 'whole world' was producing much more powerful street engines in those days....

....the 3.8 RSR had to be in a state of tune dictated by the camshafts (hardly influences BMEP) that makes it undriveable under 4500RPM just to shift max torque upwards enough in the rev range to produce about 95 HP/liter....a total joke!!!

This is where the main difference comes in: 9M produces a different engine!

The bottom end is meant to provide a stable platform that is able to sustain revs to make maximum power at minimum levels of friction.....breathing side in combination with piston/chamber design is what ultimately influences Volumetric-/Thermal Efficiency and therefore BMEP.

9M uses a completely different set of cilinderheads....therefore as stated it's a completely different engine. I think Colin has quoted 380HP to be the max of 9M development using Porsche castings.

Basically they did what Porsche already did so well in the early 70's and improved it a bit;-)

This doesn't mean btw that I believe Colin's numbers are the absolute thruth in HP/TQ. Colin has always stated his dyno is mainly used to measure relative improvements....a very worthwhile and insightful tool at that of which I sincerely hope he keeps posting results on here.

So basically what the factory top notch engineers and their unlimited budgets achieve with years of R&D can be decimated by simply slapping a Motec.

OK, but can we get the fundamentals right first. Since BMEP is purely a function of the torque produced irrespective of rpm, let's look at the actual comparative torque gain measured on the 9m dyno:
Torque of stock 993 nVR engine with 964 exhaust = 350Nm
Torque of same engine with Motec ecu, larger injectors, modified air intake (no MAF) with K&N plus 4 hours of remapping = 395Nm
Difference = 45Nm
% difference = 45x100/350 = 12.86%
It looks to me Jean that you're playing your Jokers in your first hand by comparing the 9m 395Nm to the factory figure in order to show the unrealistic gain of 19%. As I stated many posts ago, all I can base my judgements on are the comparative gains which I measure on my own dyno on cars tested under the same conditions.

By posting comparisons of 9m modified vehicles to same car pre-modification the relative gain can be clearly deduced (as above). I cannot see a flaw in that principle, but maybe others would care to comment where I am going wrong? Either way, with that in mind (provided we can all accept that the 9m dyno is an accurate comparative tool irrespective of the torque figures it calculates) I'll post another graph tomorrow comparing the 9m 3.8 race engine (as supplied to Singer) to a stock 996GT3RS tested on the 9m dyno under the same conditions. If Jean could then confirm what the factory torque is for the GT3RS we can easily calculate a correction factor from the 9m measured torque at the same rpm. By applying the same correction factor to the "Singer" 9m 3.8 Race engine we can then calculate the "Porsche Torque" of this motor and compare it to a factory 3.8RS.

If we're then all happy with the result of that, I can then post another graph showing a couple of 9m 4.0 litre variants against the same 996GT3RS and we can correct the results for a comparison to the new 997GT3RS 4.0 if you like. At that point people can come to their own decision as to whether the ex-Ilmor Mercedes engineer who designed the 9m billet head & camshafts did a good job or not. Is that fair?

Sounds more than a fair offer to me and I for one (and Im sure there will be others) look forward to drawling over some more dyno sheets :-)

I realised for myself some time ago that dyno results from operator to operator and dyno machine to dyno machine are of no real comparative use. I think there are some very wide variances.

However the relative gains on the same dyno with the same operator is really all I think we can lean on. This is something Colin has always qualified when providing his own charts.

For my own experiences I have seen approx (I say that because of arbitrary nature of the RW to FW multiplier) 13% increases in HP and 11% TQ increases as a cumulative effect on the same dyno of my own modifications. TQ increases seem to be hard to win without changes to header, heads and valve sizes - non of which I have made changes to....

OK, as promised, the first graph is the comparison between the last Singer engine built (3.82 litre, GT3 crank, 103 P&C, Billet heads, Race cams, ITB, headers, Motec, etc.) in the back of my 993RS for testing purposes against Marc's totally stock 996GT3RS when we first tested it:

The second graph is of the 9m 4.0 litre engine against the same 996GT3RS.
9m 4.0 litre power is 461.5hp @ 7194rpm, torque 489Nm (360.7lbft) @ 5459rpm.
Specific torque of 9m 4.0 is 360.7/4.0 = 90.17lbft/litre

It's no surprise that 90lbft/litre is generally regarded by experienced tuners as the practical limit for "conventional" tuning and to exceed this number requires some serious work, usually involving hundreds of hours of CFD design. Since we don't have that kind of budget I'm reasonably happy with where we are at (for now). Clearly though, the reason why the 9m engines make good power numbers is down to the shift in torque curve up the rpm band (power = torque x rpm x C), which I attribute to the synergistic design approach for of the piston/head/cam/intake/exhaust. One thing I have learned (to my cost) is that changing any one component of the system can lead to unpredictable results, but although I have seen bigger numbers occasionally the numbers posted here are pretty representative of all the 9m 3.8 Race engines we have tested.

For the record the 4.0 litre engine is the one that I raced in my 993RS CS with some success, posting new class records at most venues. One highlight was a single lap sprint at Goodwood where I won my class with a time of 89.1 seconds, the second fastest time of the day (behind an F2000 single seater driven by a local) and some 5 seconds faster than a highly developed & lightweight 996GT3RS in my class.

OK, but can we get the fundamentals right first. Since BMEP is purely a function of the torque produced irrespective of rpm, let's look at the actual comparative torque gain measured on the 9m dyno:
Torque of stock 993 nVR engine with 964 exhaust = 350Nm
Torque of same engine with Motec ecu, larger injectors, modified air intake (no MAF) with K&N plus 4 hours of remapping = 395Nm
Difference = 45Nm
% difference = 45x100/350 = 12.86%
It looks to me Jean that you're playing your Jokers in your first hand by comparing the 9m 395Nm to the factory figure in order to show the unrealistic gain of 19%. As I stated many posts ago, all I can base my judgements on are the comparative gains which I measure on my own dyno on cars tested under the same conditions.

By posting comparisons of 9m modified vehicles to same car pre-modification the relative gain can be clearly deduced (as above). I cannot see a flaw in that principle, but maybe others would care to comment where I am going wrong? Either way, with that in mind (provided we can all accept that the 9m dyno is an accurate comparative tool irrespective of the torque figures it calculates) I'll post another graph tomorrow comparing the 9m 3.8 race engine (as supplied to Singer) to a stock 996GT3RS tested on the 9m dyno under the same conditions. If Jean could then confirm what the factory torque is for the GT3RS we can easily calculate a correction factor from the 9m measured torque at the same rpm. By applying the same correction factor to the "Singer" 9m 3.8 Race engine we can then calculate the "Porsche Torque" of this motor and compare it to a factory 3.8RS.

If we're then all happy with the result of that, I can then post another graph showing a couple of 9m 4.0 litre variants against the same 996GT3RS and we can correct the results for a comparison to the new 997GT3RS 4.0 if you like. At that point people can come to their own decision as to whether the ex-Ilmor Mercedes engineer who designed the 9m billet head & camshafts did a good job or not. Is that fair?

Colin,
Ok, I will filter through the nonsense hints about jokers and th elikes, I think we are getting somewhere… So you are stating that your Motec-slapped STOCK 993 NVR engine has a higher volumetric efficiency or BMEP than say, a 996GT3 of the second generation or a 997 Carrera or a 996 Cup car?

On the other end, calling someone an amateur, especially one who gives so much wealth to the forum by sharing his developments time and time again with dyno print outs etc., imo still is uncalled for.

Questioning his (or anyone elses for that matter) theories / acheviements / claims in a polite substantiated manner is a completely different animal and has fuelled some of the greatest insights and innovations in this world.

Hi Harald,
I have been here for ten years here and I always enjoy tech discussions especially with anoraks like me, be there agreement or disagreement, but let's keep lectures about writing style away from here, especially when my comments are not directed to you and I could easily be twice your age. I appreciate that you have connection with Colin in some way, and coming in his defense is not necessary, however understandable it can be.

Yes the 1973 RSR is not the same family of engines, however it is a good find, it does seem however pretty unreasonable, given that the 3.0 version using the exact same componentry, heads and cams only achieved a BMEP of 164 and its usage was limited to over 97 Octane. As to the 3.8 993 RSR being junk, that is a very big statement. Oh, and cams and timing have a HUGE impact on VE, not the other way around.

Colin, the minute you say that we have to look at the dynos that you post in terms of Gap and comparison vs. the base it means that you aknowledge that in absolute terms your numbers are wrong, excluding any comparison.

Problem is when the peak absolute number is wrong, all the data posted raises question marks, don't you think? Especially when these runs are made with your dyno and under your own controlled environment with no independence.

I think this graph below, my "own" dyno shows very clearly the problem.

I used Singer's 360lbs of torque as read on their website or somewhere they posted. I believe the data you posted is lower, it would still be positioned ahead of every other Porsche ever built by the factory though on this graph.

The red bars is the BMEP (or VE in other words) extracted from dynos from 9M that have been posted on this forum.

I can only but imagine how exciting it must be to drive a 993 (or similar vintage) with at least the power of a 2009 GT3 RS. In a lighter package too that must be a great thrill. I think your 3.82 or 4.0l conversion would be where my lotto win money would go....

Hi Harald,
I have been here for ten years here and I always enjoy tech discussions especially with anoraks like me, be there agreement or disagreement, but let's keep lectures about writing style away from here, especially when my comments are not directed to you and I could easily be twice your age. I appreciate that you have connection with Colin in some way, and coming in his defense is not necessary, however understandable it can be.

Yes the 1973 RSR is not the same family of engines, however it is a good find, it does seem however pretty unreasonable, given that the 3.0 version using the exact same componentry, heads and cams only achieved a BMEP of 164 and its usage was limited to over 97 Octane. As to the 3.8 993 RSR being junk, that is a very big statement. Oh, and cams and timing have a HUGE impact on VE, not the other way around.

Hi Jean,

Twice my age? You drive some spectacular cars for an old fart;-)

All joking aside, I am 37 if that is in any way relevant. I know your comments weren't directed at me....I just stepped in because I didn't like what I was seeing. The discussion imo has now taken a interesting turn for the better....lots of data to run through the calculator! As far as this goes I consider myself an anorak as well.....maybe there should be an anorak section on the forum as not to bore all other readers

My connection with Colin is nothing more than the fact that he's resparked my interest in performance tuning my 964RS' engine.....the car I had initially bought to end 'wasting' money on making previous cars perform. Bullsh*t is usually king in the world of tuning, I found Colin's approach really refreshing in freely sharing dyno printouts etc. Again, just my opinion.

The 3.8RSR being junk is indeed a big statement, that in hindsight I feel some important nuance is called for. Porsche has done a great job with the 964/993 family of engines as far as durability goes. I feel there were no other sportscars in the world at that time that could match the reliability by a great margin. Outright performance is another thing:

Let's for instance take another 2Valve engine even earlier than the 2.8RSR, this time from the mid 60's 250GTO. It's 3 liter engine produces 300HP / 217lb.ft. of torque (73 lb.ft./liter - BMEP 179) and is docile enough to drive on the street, on nothing but webers and an old fashioned mechanical distributor. By the time the 3.8RSR was racing it was still producing 60/70's levels of HP&TQ/liter - BMEP 182. On the other hand you could go grocery shopping in Ferrari's then entry level street model the F355 which produced 20-30HP more from 0.3 liter less than the track RSR....a car by your own admission not wanting to do anything below 4500RPM.

Looking at build quality, cost of running and service intervals the Ferrari is a different type of animal;-)

Anyway, I'm not really impressed by the 3.8 RSR's performance.....junk is indeed to big of a word. The fact that it can be improved upon by using different heads a.o. just doesn't seem unreasonable to me.

To get back on the original subject, I think Colin's posting the readings of a stock 996 GT3 RS has put things into a good perspective:

*Porsche quotes 381HP / 285 lb.ft. for the 996 GT3 RS

*9M measures 408 / 324 lb.ft for the same car

This is a 13.6% difference in Torque. To double check 9M measures 350Nm on a stock 964 whereas Porsche quotes 310 Nm....a 12.9% difference. At the top end of the scale max power shows a smaller deviation of 7%, since power is a simple function of torque and revs - torque also differs by 7% at these revs.

This means a single lineair Porsche/9M conversion factor is non existant.

The matter is further complicated by the fact that 'mass' produced engines such as the GT3 can vary from the factory quoted figures by a 10% margin (5% up - 5% down) according to EU law. Porsche never supplied dyno figures for this specific GT3, maybe it was performing at the upper end of the scale after having been loosened up....who knows?